We all know that caterpillars turn into butterflies, and watching the end product emerge from its chrysalis and flutter away is pretty cool. Until recently, though, we'd never seen the transformation in action. As Lisa Raffensperger explains on Discover magazine's D-Brief blog:

Current methods rely on dissection of the chrysalis, or at best, staining the critter (thereby killing it) and using X-rays to look inside.

Now scientists have worked out how to use a CT scanner, used in medical settings for high-powered X-rays, to look inside a living chrysalis. And they've produced this impressive time-lapse video revealing just what goes on in that hidden interior.

The pupae studied were Vanessa cardui, destined to become Painted Lady butterflies. Each of the nine pupae was scanned a few times over its 13-16 day pupation period. Because the insects are naturally highly tolerant of radiation, and the dosages were low, more than half survived to hatching.

Here's a video made from the scans that show the change and development of the butterfly's organs.